Magnetic separator with washing and scouring means



June 20, 1967 G. H. JONES 3,326,374

MAGNETIC SEPARATOR WITH WASHING AND SCOURING MEANS Filed July 23, 1965 4 Sheets-Sheet 1 IN VENTOR T H"?[ GEORGE Hen/0y Jan/ES hwMMf W ATTORNEYS June 20, 1967 G. H. JONES 3,326,374

MAGNETIC SEPARATOR WI TH WASHING AND SCOURING MEANS Filed July 25, 1963 4 Sheets-Sheet 2 23 30 1 E J 5 T t I\\ T f I T 1 1 i4 1 6 6 11 1 Z 17 ZI/ 15' II 1 16 25 1; 20 .9 4/ 4 z hVVE/V TOR Glens: Huwey TUNES 7765M ML jaw/w ATTORNE YS G. H. JONES June 20, 1967 MAGNETIC SEPARATOR WITH WASHING AND SCOURING MEANS 4 Sheets-Sheet 5 Filed July 23, 1963 ZZZ? INVENTOH ATTORNEYS G. H. JONES 3,326,374

MAGNETIC SEFARATOR WITH WASHING AND SCOURING MEANS June 20, 1967 4 Sheets-Sheet 4 Filed July 25; 1963 [mum mmm mmm INVENTOR m I n v l f M Ha M mw ATTORNEYS United States Patent 3,326,374 MAGNETIC SEPARATOR WITH WASHING AND SCOURING MEANS George Henry Jones, Cornwall, England, assignor to Quebec smelting & Refining Limited, Montreal, Quebec, Canada, a corporation of Canada Filed July 23, 1963, Ser. No. 297,126 Claims priority, application Great Britain, July 25, 1962, 28,525/62; Aug. 1, 1962, 29,497/62 12 Claims. (Cl. 209-214) This invention relates to a method of and means for magnetically separating solid magnetic particles from a fluid in which they are suspended.

According to this invention the method of magnetically separating solid magnetic particles from a fluid in which they are suspended comprises directing the particle-carrying fluid from at least one fluid directing means to cause the particle-carrying fluid to pass through a gap which is in the path of magnetic flux from a magnetic pole, causing walls defining the gap to move about an axis substantially parallel to the direction of the flow of the particlecarrying fluid within the gap, such that the particle-carrying fluid is caused to pass through the gap and successively directing through the gap a flow of scouring fluid at a pressure sufiicient to remove magnetic particles adhering to the walls of the gap. There may be successively directed through the gap a flow of particle-carrying fluid, a flow of washing fluid and a flow of scouring fluid, and the walls of the gap may be moved in rotational movement so that a portion of the gap defined by a given portion of walls has successively passed through it particle-carrying fluid, washing fluid and scouring fluid from stationarydirecting means.

Means according to the present invention for magnetically separating solid magnetic particles from a fluid in which they are suspended comprise an assembly comprising a support, capable of rotation about an axis, to which is fixed means to define two sides of at least one gap, the assembly being placed adjacent a pole of a permanent or electromagnet, and fluid directing means mounted outside one end of the gap, and fluid collecting.

means mounted outside the other end of the gap for fluid flow between the directing and collecting means through the gap, the fluid flow being in a direction substantially parallel to the axis of rotation of the support.

The gap defining means may be cylindrical rings, curved plates or planar plates to define annular, segmented annular or segmented polygonal gaps respectively. There may be a single gap or a plurality of gaps or a plurality of segmented gaps.

A hood may be provided to enable fluids to be directed through the gap and the hood may be movable towards or away from the gap.

In this specification magnetic particle, as is usual in the art, means a ferromagnetic particle which under the influence of a magnetic field is attracted to a position of maximum flux density.

Particular embodiments of the invention and ways of carrying it into elfect will now be described with reference to the accompanying drawings wherein:

' FIG. 1 is a plan view on the line II, FIGURE 3 of a first embodiment of the invention.

FIG. 2 is a plan view on the line II'II, FIGURE 3 of the embodiment.

FIG. 3 is a side sectional elevation of the embodiment.

FIG. 4 is a plan view on the line IV-IV, FIGURE 5 of a second embodiment of the invention.

FIG. 5 is a sectional side elevation of the second embodiment.

3,326,374- Patented June 20, 1967 FIG. 6 is a diagrammatic plan view of a modified arrangement of parts of the embodiments.

FIG. 7 is a detail side sectional view of a part of the embodiments.

FIG. 8 is a plan view of a third embodiment of the invention.

FIG. 9 is a developed side sectional elevation of part of the embodiment of FIG. 8.

FIG. 10 is a sectional view of a part of the mechanism provided in any of the embodiments.

FIG. 11 is a plan view of elements used in the embodiments.

FIG. 12 is a side elevation of one of the elements shown in FIG. 11.

FIG. 13 is a plan view of part of a modified embodiment of the invention.

In the embodiments shown in FIGS. 1, 2, and 3 and parts of which are shown in detail in some other figures, rings 1 and 2 spaced apart radially by non-magnetic spacers to allow fluid flow through the annular gaps thus formed, the rings being of a nature which will be described more fully later, are mounted fast with a center plate or disc 3 of magnetic material which is itself mounted for rotation on a shaft 4. Radial ring supports 6 extend from the shaft 4 to the bottom of the rings 1, 2 and are narrow and small in number so as not to impede the flow of fluid between the rings 1, 2. The shaft 4 is mounted in a bush 7 in the main housing 9 of the apparatus, and a sprocket wheel or other driving device 10 is provided so that the shaft 4, radial supports 6, disc 3, and rings 1, 2 can be driven to rotate together. The housing 9 is cylindrical in form and has mounted at its top surface a fixed, stationary ring 11 having inwardly projecting teeth 12 which comprise the cores of electromagnets whose windings are indicated at 13. The inner face of pole piece of each of the electromagnets is shaped as shown at 14 to follow the contour of the portion of the ring 2 which is adjacent them. The electromagnets are arranged such that north and south poles (N, S respectively in FIG. 1) are disposed alternately about the ring and are as near as possible to the shaped wall 14. Below the rings 1, 2 and extending completely under them are a series of troughs 16, 17, 18 which are associated with channels or launders 20, 21, 22 respectively. The upper ends of the troughs 16, 17, 18 are substantially planar at their upper surface as indicated at 24 in FIG. 3, but have a tongue or flange 25 projecting upwardly beyond the outermost circumference of the supporting arm 6 and rings 2. In plan, as seen in FIG. 2, the upper ends 24 of the troughs 16, 17, 18 are in the shape of annular segments, the trough 18 having a longer circumference than the troughs 16, 17. The channels 20, 21, 22 are connected to the troughs 16, 17, 18 respectively to carry away matter collected by the troughs. Above the upper end of the rings 1, 2 are provided, at intervals around the circumference of the stationary ring 11, feed hoppers 27, washing jets 28, of the same form as hoppers 27 but distinct from them, and scouring jets 30. The feed hoppers or wash jets 27, 28 are feed from above the pipes 31 and the scouring jets 30 by high pressure supply of fluid through pipe 32. These devices 27, 23, 30 are mounted above the rings as shown in FIG. 3 and are provided with protective and collecting sleeves 33 to prevent overflow of the fluid supply through the devices, and are disposed around the circumference so that, as best seen in FIG. 3, a device 27 is mounted above a trough 18, the wash jets 28 are mounted above a trough 17 and the scouring jets are mounted above a trough 16. The feeding devices and troughs 18 are at a position opposite electromagnets 12 so that the rings above these troughs are the most highly energised magnetically, and the scouring jets 30 and troughs 16 are mounted midway between the electromagnets where the magnetic field acting on the rings is weakest, due to the alternating polarity of successive magnets round the ring 11.

' In addition air jets 34, best seen in FIG. 7 may be mounted next to one scouring jet 30 in order to remove any oversize or highly magnetic particles which would clog the spaces between the rings. The particles are removed by a blast of compressed air from the jet 34 passing upwardly through the gap between the rings into a hood 35. The jet 34may be part of an assembly to be described in more detail with reference to FIG. 10. It is to be noted that the direction of the air flow from the jets 34 is the opposite to that to the feeding, washing and scouring jets, and the base of jets 34 would penetrate the floor of troughs 18.'It is desirable that the compressed air used for supplying the jets 34 should be heated since the adiabatic expansion and consequent cooling of this gas might cause moisture to freeze on the rings 1,2.

The rings 1 may be made up of wire, fibres, particles or pieces of magnetic material embedded in non-magnetic material as described in my co-pending United States application Ser. No. 281,529, where there is described and claimed a member or members (the rings of the present invention) consisting of at least elements of magnetic material held in a matrix of non-magnetic material, or may be made of thin strip of ferromagnetic material, and may be provided with grooves generally as shown in FIGS. 12 and 13. The direction of flow of fluid past the rings shown in FIG. 1, would be into the plane of the paper and longitudinally of any grooves provided in the rings. The rings 2 may be of similar material or may be of ferromagnetic material, usually the same as the rings 1.

In operation, the shaft 4 is driven to rotate in the sense of the arrow A, FIG. 2,and takes with it the rings 1, 2 and center plate 3, and the feeding, washing and scouring jets are set in operation. Fluid passes through the pipe 31 and brings with it a suspension of mixed ferromagnetic and non-magnetic material particles. It is passed through the hopper 27 and the protective sleeve 33 onto a portion of the rotating plates 1, 2 at a point near the shaped-wall 14 of an electromagnet 12. The magnetic forces acting on the rings cause the magnetic particles to be adhered to the rings particularly at projections between grooves in the rings, which are points of high flux density. Non-magnetic particles are not, in general, so adhered, and fall with the fluid to troughs 18, and then are taken away through launders 22. The portion of rings 1,2 which we are considering, continuously rotating, then passes to the area above troughs 17 at which point they are acted on by washing fluid fed through a hopper 28, and non-magnetic material is washed by the low pressure washing fluid into the trough 17 whence it is removed by launder 21. The portion of ringswe are considering then passes to below the jets 30 and above the troughs 16 at which point the magnetic field passing through the rings is at its lowest and in fact should practically be zero, due to the alternation of polarities of adjacent magnets 12. Scouring jets act on the magnetic particles which are washed ofl? the rings into launders 20 whence they are collected.

Between one set of scouring jets 30 and a feed hopper 27 the portion of the rings passes between air jets 54 and hood 35 so that oversize particles are removed, passing the air jet 30 once in each complete revolution of the rings.

In a modified form of the invention shown in FIGS. 4 and 5, permanent magnets 40 are mounted on the outer ring 11 to provide alternate polarity at their faces nearer the rings 1, 2. Pole pieces 44 are provided to follow the circumference of the rings. In this embodiment of the invention only three rings 1, 2, two extreme rings 2 and one inner ring 1, are provided as against the four in the first embodiment. Above the shaft 4, radial ring supporting spokes of spider 41 support the rings only, and the center plate 3 is replaced by center piece 42 of magnetic material about whose edges are provided permanent magnets 43, with pole pieces 44 to follow the inner circumference of the inner ring 2, and disposed to provide a polarity which is opposite to that of the corresponding magnet projecting inwardly from the outer ring 11, and alternating in pairs about the ring 11. The center piece 42 and its associated magnets are supported on a framework 46 for feeding, washing and scouring devices which are as in the first embodiment except that only two scouring jets 30 are provided instead of the three which were necessary before since now only two annular gaps between rings 1 and 2 need to be scoured.

The working of this device is as described for the previous embodiment.

Of course electromagnets may be substituted for magnets 40 and 43.

FIG. 6 shows diagrammatically one arrangement of the various washing and scouring jets above the respective troughs 16, 17, 18. It can be seen here that the troughs 17 have been elongated to accommodate two feeding hoppers 27 side by side adjacent the face of the magnet. When the rings rotate, in the sense of arrow A, the portion of the rings then successively passes to the narrow trough 18 where a washing jet 28 is directed on to the rings and then to a scouring jet 30 mounted above the elongated trough 16. An air jet 34 together with its associated hood is passed only once in one revolution of the rings and lies between the scouring jet 30 and the feeding hopper 27 of that part of the apparatus, It may be necessary to displace the troughs slightly angularly, about the circumference of the rings, to allow for the eifect of the moving rings sweeping fluid and particles sideways, and the side walls of the tops of the trough may be, in plan view, at an angle to a radius from the shaft, or may be curved.

A third modification of the invention is shown in FIG. 8 and in FIG. 9. The rings 1 and 2 are replaced by a series of curved plates 50, 51, 52, which are disposed coaxially of the shaft around the circumference of a support such as 6 or 41 to form non-continuous rings. The plates 50, 51, 52 are spaced apart to provide annular segmental gaps 55 between them, and are separated by non-magnetic material which forms co-axial walls 56 at the inner circumference of plates 52 and the outer circumference of plates 50, and radial walls 57 between the ends of adjacent plates 50, 51, 52. The walls extend above and below the level of the tops and bottoms of the plates 50, 51, 52, respectively. As shown in FIG. 9, which is a developed side sectional elevation, the scouting jets 30 and air jets 34 are mounted within movable hoods 60, which are shown in more detail in FIG. 10. The hood 60 comprises a hollow body portion 62 having at its lower end an inlet pipe 63 connected to a flexible hose (not shown). A shoulder portion of the pipe 64 at the base of the body 62 provides a seating for a valve 66. A rubber gasket or sealing ring 69 projects below the shoulders 64 and is of a shape such that it can fit over and slightly Within the projecting walls 56, 57 about the plates 50, 51, 52. A pneumatic double acting ram 70 connects the body 62 to a frame 71, which may be the frame 46 described with reference to FIG. 5, or which may be specially provided, and which ram can be activated to depress or withdraw the hood 60 as a Whole. Bushes 72 in the frame 71 provide a sliding bearing for rods 74 projecting from the upper portion of the body 62. Within the body 62 a pneumatic cylinder 75 acts on the stem 76 of the valve 66 and can withdraw or apply the valve to the shoulder 64 independently of any movement of the body 62 as a whole, A hood 60 is applied above the plates 50, 51, 52 if it is to supply scouring water and below them if it is to supply an air blast.

In operation, the shaft and the plates are rotated intermittently, for instance by a reciprocating rod engaged near the circumference of the rings, at each stroke in a given direction, each step of movement being through the angle subtended at the shaft by one set of plates 50, 51, '52. Above the segments denoted 101, feed hoppers 27 are situated. Above the segments denoted 102, a washing hopper 28 is situated, at segment 103 no device is provided, and at the segment 104 scouring hood 60- and jets 30 and/ or hood 60 and air jet 34 are provided, which hoods are lowered onto the gaps during the pause in rotation.

The only devices needing the hood 60 are the high pressure devices, namely the scouring jet 30 and the air jet 34. The other devices for feeding and washing may be as described for the other embodiments, but the feeding and washing may not be continuous, or hoods used may be used additionally for feeding and washing fluid supply.

The separator shown in FIGURE 8 is provided with four magnetic poles 78 about its circumference and with 25 annular segments made up of sets of plates 50, 51, 52. Feeding and washing is performed in front of poles and scouring between poles. At the position of the segment 103 the magnetic field is insuflicient for feeding or washing purposes but is too strong for scouring, and for greater efi-iciency in separating fractions segments at that position are not acted on by devices.

In a modification of the embodiment shown in FIG- URE 8, which modification is shown in FIG. 13 plates 58 are planar but have grooved surfaces, like planar plates 59. FIGURE 13 shows the means for spacing apart the plates 58 (or plates 50, 51, 52) by the nonmagnetic material extending from the walls 57.

In a further modification, the plates 50, 51, 52 may be replaced -by rings 1, 2, but with the annular gaps between them divided up into segments by walls 57, and with walls 56 surrounding them at the outer and inner circumference.

The center plate of the intermittently rotating embodiment may rotate with the plates or rings in the same way as center plate 3, or may be stationary and bear magnets as did the center piece 42.

In any of the embodiments described:

(a) The plates or rings may be thinner at their top (feed end) than at their bottom, so that the gap is wider at that end than it is at the bottom, to allow greater build up of magnetic or other material at that end without clogging the gap between the plates.

b) The single unit air jets may be replaced by double jets pointing upwards at an angle to each other, if particles to be cleared are likely to be extra heavy or large, and to clear the portions of rings lying above the support spokes 6 or 41.

(c) The poles of the outer array of magnets or of the inner array, when provided, may be linked within the array.

(d) The embodimnets may be modified to be used to separate magnetic particles from a gaseous fluid rather than a liquid fluid. Modification would be required in the means for delivering the fluids to the separator, and for collecting them after separation. The washing and scouring jets can also be in the form of air or other gas jets.

(e) The innermost and outermost rings (2 or plates 50, 52) may be made of stronger material and of greater thickness than the intermediate rings 1 or plates 51.

(f) The outermost ring or plate may be formed in such a way that its magnetic permeability is greater in a direction radial to the shaft than in a tangential direction. Such an arrangement may be a ring composed of radial laminations of ferromagnetic material held together by nonmagnetic compound, with or without holes in the laminated material extending in a tangential direction and wires or rods passing through the holes.

(g) One or more sets of particle collecting rings and associated plates and center pieces may be fixed to one shaft.

" In a modified form of the hood described with reference to FIGURE 10, a movable mounting may be provided so that the hood can follow a certain amount of movement of continuously rotating rings or plates. The hood may be pressed on to the wall about the plates and carried with them, its supporting arm's travelling through a shaped slot against a spring loading. When the hood is withdrawn from the walls the spring takes the hood back to its original position.

Alternatively the air jet may be may mounted to be driven by a cam arrangement so that a single jet traverses gaps lying parallel to one another, one being cleared completely during one revolution of the assembly and its neighbour during the next revolution. The jet may be operated continuously or intermittently.

Rotation of the rings of the continuously moving embodiments is preferably at a constant speed.

While a number of different forms of separator have been described above, it will be understood that the invention is not restricted to the particular form of separator or to the constructional details described, since it will be obvious that many variations, both in the general arrangement of the separator and in its details are possible Without departing from the scope of the invention.

In particular, plates or rings may be formed with angular grooves whose peaks touch the adjacent plate or ring to define triangular gaps arranged circularly or polygonally about the axis of rotation of the support of the plates or rings as centre.

I claim V 1. A method of magnetically separating solid magnetic particles, suspended in a carrying fluid, from the carrying fluid and from non-magnetic particles also suspended in the carrying fluid, said method comprising the steps of: providing walls defining an annular gap; rotating the gapdefining walls about an axis of rotation, whereby the annular gap moves along an annular path coincident therewith; applying to the gap, at at least one first portion of the annular path, a strong magnetic field; directing the carrying fluid to flow through the gap at at least one first portion of the annular path and in a direction substantially parallel to the axis of rotation, to cause at least the solid magnetic particles to adhere to the gap-defining Walls; at at least one second portion of the path succeeding a first portion and still within the zone of the magnetic field, directing a washing fluid to flow through the gap substantially parallel to the axis of rotation, to wash any non-magnetic particles from the gap-defining walls; at at least one third portion of the path succeeding a second portion and within a zone of substantially zero magnetic field, directing a scouring fluid to flow through the gap substantially parallel to the axis of rotation, at a pressure suflicient to remove magnetic particles adhering to the gap-defining walls; and, at at least one fourth portion of the annular path, directing a current of fluid through the annular gap in a direction opposite to flow of the scouring fluid therethrough and substantially parallel to the flow of scouring fluid, and while the fourth portion of the annular gap is Within a zone of substantially zero magnetic field.

2. A method, as claimed in claim 1, in which said current of fluid is an air blast.

3. A rotary magnetic separator for magnetically separating solid magnetic particles, suspended in a carrying fluid, from the carrying fluid and from any non-magnetic particles also suspended in the carrying fluid, said separator comprising, in combination, a support; means mounting said support for rotation about a substantially vertical axis; means fixed to said support and defining at least one gap rotatable with said support and divided into a plurality of adjacent sections, the gap extending substantially parallel to said axis; a magnetic field producing means in operative association with said gap and providing zones of strong magnetic fields and weak magnetic fields alternating in the direction of rotation of said gap; carrying fluid directing means mounted adjacent the entrance of said gap in zones of strong magnetic field; fluid collecting means mounted adjacent the exit of said gap in zones of strong magnetic field; said fluid directing and collecting means providing for fluid flow through the gap therebetween and substantially parallel to the axis of rotation of said support; means directing washing fluid to flow through said gap in zones of strong magnetic field; means directing scouring fluid to flow through said gap in zones of substantially zero magnetic field; and at least one fluid directing means situated adjacent the discharge end of said gap and operable to direct an air blast through the gap in a direction opposite to the direction of fluid flow through the gap and in a zone of weak magnetic field.

4. A rotary magnetic separator, as claimed in claim 3, wherein said means defining said gap are curved plates arranged to form a segmented annular gap.

5. A rotary magnetic separator, as claimed in claim 3, wherein said means defining said gap are planar grooved plates arranged to form a segmented polygonal gap.

6. A rotary magneticseparator for magnetically separating solid magnetic particles, suspended in a carrying fluid, from the carrying fluid and from any non-magnetic particles also suspended in the carrying fluid, said separator comprising, in combination, a support; means mounting said support for rotation about a substantially vertical axis; means fixed to said support and defining at least one gap rotatable with said support and divided into a plurality of adjacent sections, the gap extending substantially parallel to said axis; a magnetic field producing means in operative association with said gap and providing zones of strong magnetic fields and weak magnetic fields alternating in the direction of rotation of said gap; carrying fluid directing means mounted adjacent the entrance of said gap in zones of strong magnetic field;fluid collecting means mounted adjacent the exit of said gap in zones of strong magnetic field; said fluid directing and collecting means providing for fluid flow through the gap therebetween and substantially parallel to the axis of rotation of said support; means directing washing fluid to flow through said gap in zones of strong magnetic field; means directing scouring fluid to flow through said gap in zones of substantially zero magnetic field; said means defining said gap being cylindrical rings; and a plurality of radial partitions dividing the annular gap formed by said cylindrical rings into circumferentially adjacent segments; said partitions being made of non-magnetic material and extending above and below the respective axially opposite ends of said cylindrical rings, and being provided at the outermost and innermost peripheries of said rings.

7. A rotary magnetic separator, as claimed in claim 4, in which said curved plates are arranged in groups around said. support to form non-continuous rings, the curved plates in each group being spaced apart to provide annular segmented gaps therebetween; the plates and the groups of plates being separated by walls of non-magnetic material extending above and below the respective axially opposite ends of the plates.

8. A rotary magnetic separator, as claimed in claim 7, including two air blast nozzles provided at one portion of the gap and directed upwardly at an angle to one another.

9. A rotary magnetic separator, as-claimed in claim 7, in which said means directing the scouring fluid to flow through the gap comprises a hood having a body portion; valve operated means within said body portion operable to provide for or to interrupt flow of scouring fluid into the gap; means operable to move said body portion and said valve toward and away from the entrance of said gap; and fluid-tight seal means on one of said body portion and said gap-forming means forming a fluid tight seal upon engagement of said body portion with said gap forming mean-s. p

10. A rotary magnetic separator for magnetically separating solid magnetic particles, suspended in a carrying fluid, from the carrying fluid and from any non-magnetic particles also suspended in the carrying fluid, said separator comprising, in combination, a support; means mounting said support for rotation about a substantially vertical axis; means fixed to said support and defining at least one gap rotatable with said support and divided into a plurality of adjacent sections, the gap extending substantially parallel to said axis; a magnetic field producing means in operative association with said gap and providing zones of strong magnetic fields and weak magnetic fields alternating in the direction of rotation of said gap; carrying fluid directing means mounted adjacent the entrance of said gap in zones of strong magnetic field; fluid collecting means mounted adjacent the exit of said gap in zones of strong magnetic field; said fluid directing and collecting means providing for fluid flow through the gap therebetween and substantially parallel to the axis of rotation of said support; means directing washing fluid to flow through said gap in zones of strong magnetic field; means directing scouring fluid to flow through said gap in zones of substantially zero magnetic field; means operable to rot-ate said support intermittently; a hood operatively associated with said gap; a stationary bush; and a sliding bearing for said hood working in said bush, for movement of said hood toward and away from said gap.

11. A rotary magnetic separator for magnetically separating solid magnetic particles, suspended in a carrying fluid, from the carrying fluid and from any non-magnetic particles also suspended in the carrying fluid, said separator comprising, in combination, a support; means mounting said support for rotation about a substantially vertical axis; means fixed to said support and defining at least one gap rotatable with said support and divided into a plurality of adjacent sections, the gap extending substan tially parallel to said axis; a magnetic field producing means in operative association with said gap and providing zones of strong magnetic fields and weak magnetic fields alternating in the direction of rotation of said gap; carrying fluid directing means mounted adjacent the entrance of said gap in zones of strong magnetic field; fluid collecting means mounted adjacent the exit of said gap in zones of strong magnetic field; said fluid directing and collecting means providing for fluid flow through the gap therebetween and substantially parallel to the axis of rotation of said support; means directing washing fluid to flow through said gap in zones of strong magnetic field; and means directing scouring fluid to flow through said gap in zones of substantially zero magnetic field; said gap decreasing in Width, radially of said vertical axis, from its entrance end to its exit end.

12 A rotary magnetic separator for magnetically separating'solid magnetic particles, suspended in a carrying fluid, from the carrying fluid and from any non-magnetic particles also suspended in the carrying fluid, said separator comprising, in combination, a support; means mounting said support for rotation about a substantially vertical axis; means fixed to said support and defining at least one gap rotatable with said support and divided into a plurality of adjacent sections, the gap extending substantially parallel to said axis; a magnetic field producing means in operative association with said gap and providing zones of strong magnetic fields and weak magnetic fields alternating in the direction of rotation of said gap; carrying fluid directing means mounted adjacent the entrance of said gap in zones of strong magnetic field; fluid collecting means mounted adjacent the exit of said gap in zones of strong magnetic field; said fluid directing and collecting means providing ,for fluid flow through the gap therebetween and substantially parallel to the axis of rotation of said support; means directing washing fluid to flow through said gap in zones of strong magnetic field; and means directingscouring fluid to flow through said gap in zones of substantially zero magnetic field; the gap-defining means comprising plates having angular 9 grooves formed in their facing surfaces and extending in the direction of flow through the gap; the apieces of ribs defining adjacent grooves in the respective plates touching each other to define a series of triangular cross section gaps.

References Cited UNITED STATES PATENTS 455,984 7/1891 Fiske 209-223 762,753 6/1904 Payne 209-219 821,615 5/1906 Dings 209220 1,076,213 10/1913 Langguth 209228 X FOREIGN PATENTS 8/ 1962 Canada.

3/ 1912 Great Britain. 5/ 1926 Great Britain. 2/1957 Great Britain.

FRANK W. LUTTER, Primary Examiner.

HARRY B. THORNTON, R. HALF-ER,

Assistant Examiners. 

1. A METHOD OF MAGNETICALLY SEPARATING SOLID MAGNETIC PARTICLES, SUSPENDED IN A CARRYING FLUID, FROM THE CARRYING FLUID AND FROM NON-MAGNETIC PARTICLES ALSO SUSPENDED IN THE CARRYING FLUID, SAID METHOD COMPRISING THE STEPS OF: PROVIDING WALLS DEFINING AN ANNULAR GAP; ROTATING THE GAPDEFINING WALLS ABOUT AN AXIS OF ROTATION, WHEREBY THE ANNULAR GAP MOVES ALONG AN ANNULAR PATH COINCIDENT THEREWITH; APPLYING TO THE GAP, AT AT LEAST ONE FIRST PORTION OF THE ANNULAR PATH, A STRONG MAGNETIC FIELD; DIRECTING THE CARRYING FLUID TO FLOW THROUGH THE GAP AT AT LEAST ONE FIRST PORTION OF THE ANNULAR PATH AND IN A DIRECTION SUBSTANTIALLY PARALLEL TO THE AXIS OF ROTATION, TO CAUSE AT LEAST THE SOLID MAGNETIC PARTICLES TO ADHERE TO THE GAP-DEFINING WALLS; AT AT LEAST ONE SECOND PORTION OF THE PATH SUCCEEDING A FIRST PORTION AND STILL WITHIN THE ZONE OF THE MAGNETIC FIELD, DIRECTING A WASHING FLUID TO FLOW THROUGH THE GAP SUBSTANTIALLY PARALLEL TO THE AXIS OF ROTATION, TO WASH ANY NON-MAGNETIC PARTICLES FROM THE GAP-DEFINING WALLS; AT AT LEAST ONE THIRD PORTION OF THE PATH SUCCEEDING A SECOND PORTION AND WITHIN A ZONE OF SUBSTANTIALLY ZERO MAGNETIC FIELD, DIRECTING A SCOURING FLUID TO FLOW THROUGH THE GAP SUBSTANTIALLY PARALLEL TO THE AXIS OF ROTATION, AT A PRESSURE SUFFICIENT TO REMOVE MAGNETIC PARTICLES ADHERING TO THE GAP-DEFINING WALLS; AND, AT AT LEAST ONE FOURTH PORTION OF THE ANNULAR PATH, DIRECTING A CURRENT OF FLUID THROUGH THE ANNULAR GAP IN A DIRECTION OPPOSITE TO FLOW OF THE SCOURING FLUID THERETHROUGH AND SUBSTANTIALLY PARALLEL TO THE FLOW OF SCOURING FLUID, AND WHILE THE FOURTH PORTION OF THE ANNULAR GAP IS WITHIN A ZONE OF SUBSTANTIALLY ZERO MAGNETIC FIELD. 